1. Field of the Invention
This invention relates to the field of disinfecting or sterilizing agents. More particularly this invention is a disinfectant/sterilizing agent, which is water soluble, safe to the human body and is intended for application to perishable foods such as poultry, beef, pork and cut vegetables for killing or stopping the growth of pathogenic microorganisms to thereby disinfect or sterilize the food.
2. Description of the Related Art
Before selling meat such as chicken, beef and pork for consumption, it is necessary to stop or retard the growth of pathogenic microorganisms and it is preferable to kill pathogenic microorganisms such as bacteria or virus especially Salmonella, and E-coli 0-157, which may cause food poisoning due to their presence in the meat.
In order to kill or stop or retard the growth of these pathogenic bacteria or otherwise render them harmless, conventional disinfectant or sterilizing materials are used. Conventional disinfectants or sterilizing include alcohol, sodium hypo chlorite liquid, and sodium phosphate which are applied by spraying or soaking the meat in a liquid containing one or more of the above chemicals.
However, these prior art methods are not satisfactory for providing the desired disinfecting or sterilizing effect on pathogenic microorganisms such as bacteria.
For example, sodium hypo chlorite is most frequently used in tap water supply system or on other foods because sodium hypo chlorite is basically alkali and can be used with strong acid materials such as acetic acid or fruit acids to kill bacteria. However, the containers which carries these acid agents tend to rust and corrode, and due to the durability of the container and the elution of metal ions, it is difficult to utilize such agents as a food disinfectant.
Sodium phosphate has a narrow spectrum of efficacy on the bacteria and is effective in disinfecting the salmonella and coli-forms but it is not effective on listeria or staphylococcus groups of bacteria.
When alcohol is used as a disinfecting/sterilizing agent, there is the problem of residual smell of alcohol in the foods. It is rather difficult to completely remove the smell of alcohol from foods even after the food has been well rinsed with water after application. The loss of natural taste and smell associated with the use of alcohol degrades the commercial value of the food and also, the application of alcohol to certain foods is not allowed by regulation.
Hinokitiol (xcex2-Thujaplicin) is safe to the living body, does not have the characteristics of metal corrosion, and has a wide spectrum of disinfecting/sterilizing of bacteria/virus. However, due to its low solubility in water, it is hard to make an agent which has a sufficiently high concentration of hinokitiol against the bacteria. Liquids containing a low concentration of hinokitiol is not economical cost wise, especially when consideration is given to transportation costs to transport the solution to the place of usage. Therefore it is necessary to manufacture a solution containing high concentration of hinokitiol, and dilute it at place of usage.
On this point of view, recently, in order to increase the efficacy against bacteria and to meet the requirement of accessibility, there have been a few proposals in the patent literature to concentrate hinokitiol in liquid form with combination of other ingredients. For example, the combination of hinokitiol with phenoxyethanol (in JP 2-243607) is said to have enhanced efficacy on Pseudomonas aerginosa, Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albicans, Aspergillits niger and is said to be useful for cosmetic application. JP 5-271073, discloses the combination of hinokitiol and indole, and indicates that the composition has an enhanced efficacy on Pseudomonas aerginosa. In JP 9-12423, a urea containing hinokitiol solution is indicated as a disinfectant, in which it is used in cosmetics such as body lotion, shampoo, and lipstick, as well as in other applications such as mouthwash as a preventive aid for blennorrhoea alveolaris and bad breath, and tooth paste.
However, there is no proposed usage for an aqueous hinokitiol liquid to disinfect or sterilize perishable foods by soaking or spraying directly on foods. In applying hinokitiol to foods, it is important to avoid degradation of food taste/smell. Also, because hinokitiol has a strong or stimulating odor, it is necessary to include additives to neutralize such stimulating odor or taste and to increase its water solubility. Urea or indole is unsuitable as an additive because these compounds have a strong odor and cannot be used for foods. Disinfecting agents that contain urea or alcohol are not to be used on foods due to safety considerations. These are the reasons that the above patents of hinokitiol in aqueous solution as disinfectant cannot be directly applied to foods.
An example for food application is seen in JP 9-241205. Sucrose fatty acid ester, which has a hydrophilic/lipopholic balance index of more than 17, is combined with hinokitiol for dilution in water. Sucrose fatty ester is a surface active agent and facilitates water solubility of hinokitiol. It is not forbidden to use sucrose fatty acid ester as food additive. However, when sucrose fatty acid ester is mixed with hinokitiol, it loses some of its antibacterial efficacy.
This invention solves the drawbacks of hinokitiol, which are its stimulating or strong objectionable odor and taste and difficulty of dissolving in water, and takes advantage of its safety as a food additive in perishable foods by the addition of other plant extracts.
The aqueous disinfecting/sterilizing agent of this invention is a mixture which comprises water, hinokitiol and at least one of the following extracts of aloe vera, green tea, low striped bamboo, and dokudami.
This invention provides a method of utilizing an aqueous disinfecting/sterilizing agent on perishable foods.